Who wants a bread puck?

Next time you find yourself in the kitchen with an empty bowl and a box of cereal, stop and consider how much a 1/2 cup serving of cereal would be. Go ahead, pour that cereal out. Stop when you think you've got 1/2 cup. Now, grab a measuring cup and see how much is in that bowl.

Did you actually pour out one cup of cereal? Probably not, says Dr. Donald Hensrud, chairman of the division of preventive medicine at the Mayo Clinic in Rochester, Minn., and medical editor in chief behind newly revised "The Mayo Clinic Diet." If you're like me, you probably had more; the book lists a typical portion as 11/2 cups.

This simple exercise underscores a growing problem: The difference between real-life portions and serving sizes. A portion is what you put on your plate, but a serving is usually a specific amount, often specified in a diet plan or used to provide nutritional information on a food label. While it may seem like a minor thing, this dietary discrepancy can spell added pounds, added inches and, most important, added health risks.

"In diet plans, a certain number of servings from each food group is sometimes recommended to control the total number of calories," Hensrud said.

Get back on track by eye-balling more accurately the food in front of you to determine how much you should eat. After all, as Hensrud points out, you can't live your life armed with a scale or a set of measuring cups. Even if you could, that sort of attention to detail can grow stale pretty fast.

So estimate, approximate, look and think before you eat. For as one of the tips in the Mayo books notes, "If you control portion size, the calories tend to take care of themselves."

Like some other diet and nutritional guides, the Mayo book urges you to visualize some very familiar everyday object when determining how much is just right for you: Think one or two dice when scooping up the butter, a deck of playing cards when portioning a piece of fish, a hockey puck or half a bagel when reaching for that loaf of whole-grain bread.

Now, if you choose to eat two hockey pucks worth of carbs at a meal instead of one that's up to you. But the smart eater will make adjustments to what they eat later in the day to keep their diet in balance.

"People are going to make their own choices," Hensrud concedes. "All we can do is help with tools to approximate portions and serving sizes. Once you get it, it becomes second nature."

Need more help determining sizes? Consider downloading, printing and laminating a wallet-sized serving size card from the National Heart Lung and Blood Institute (hp2010.nhlbihin.net/portion/servingcard7.pdf). For example, the card considers 11/4 ounces of cheese coming in as two cheese slices or 4 stacked dice, and translates 2 tablespoons of peanut butter as the equivalent of two ping-pong balls. The institute also has a "portion distortion" online quiz you can take.

The Web site http://www.choosemyplate.gov is sponsored by the U.S. Department of Agriculture's Center for Nutrition Policy and Promotion. It suggests measuring how much the bowls, cups, plates you use actually hold. Then measure out a fixed serving, 1 cup of juice for example, to see what it looks like in your glass.

"A simple trick to help you eat less is to use a smaller plate, bowl or glass," the program's website reads. "One cup of food on a small plate looks like more than the same cup of food on a large plate."

Also consider what proportion of a plate various foods should occupy. The Mayo book says vegetables and fruits should take up about half of the plate, carbohydrates one-quarter of the plate and the remaining areas should be for meat and dairy items.

Try not to think of all this in a glass is half-empty sense. Hensrud notes serving sizes for vegetables, and fruits to a lesser extent, are there to make sure you getting the minimal amount for healthy eating.

"Don't focus on what you can't eat but what you can eat," Hensrud said. "People say they like fruit, but fruit doesn't enter most diets on a daily basis. So, keep a fruit bowl around and reach for it first… If you are eating fruit you are probably not eating something higher in calories."

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